I know some other people have gotten actual negative disposable income in a manner that is not a bug. However if you look at the things contributing to this persons income and where they are on the graph it looks to me more like an overflow number error than that this person actually has a negative disposable income. I can send the game file later too if that will be helpful.
Hmmm interesting :D. TBH I kind of regret introducing that whole tab on the charts, because although it is interesting to look at, there are multiple situations where the actual maths goes a bit crazy. Its difficult because the game tends to work almost everything in terms of percentages, but then this screen tries to backwards-justify a lot of that into actual integer values for dollars, and although 99% of the time its fine, there are definitely outliers!
Judging just from that screenshot, I’d guess that you have really high taxes (maybe sales or income tax?) and super-high values for a lot of environmental subsidies? It looks like this voter is being taxed into debt, but then bailed back out by green policies?
I only have 48% income tax though adding the negative values to the persons original income does get a negative number and then adding back the positives at least for 1 example does not give the magnitude of the negative disposable income though what you suggested does sort of appear to be what is happening. I am at 99% socialist and liberal. If you want to take a look through it I can email you the save file? On a side I somehow did this my first time playing the game again since like alpha 1.03 or something.
I think that screen does tend to break down a bit when it comes to games that are that far to one of the corners of the political compass.
Funnily enough the actual core simulation underneath it copes with it ok. Its just with the maths required to try and fudge peoples actual numeric income from the other data, you get oddities 